Since it is not easy to remember all states and their meanings, Microsoft has enhanced the error messages in Errolog, and now shows reasons as well. In earlier versions of SQL Server, the “Reason: … ” section was not available, and state was the only way to find the cause. State is very important in the error message. Reason: Password did not match that for the login provided. 10:58:19.400 Logon Login failed for user 'sa'. Below are some error messages which we have seen a lot, taken from SQL Server 2014. Under startup parameters, we need to look at -e which stands of path of Errorlog. The location of the file can be found using SQL Server Configuration Manager. The way to troubleshoot these errors is to look into the SQL Server Errorlog. (Microsoft SQL Server, Error: 18456)įor security reasons (and to a hacker’s disadvantage), SQL Server avoids revealing the exact cause of error message. The error message received by the client would as shown below: Login failed for user 'username'. This second scenario results from authentication or security related errors. Scenario 2: Login request reaching SQL Server and then failing (Note that ping is the best test to find name and IP address mapping). Incorrect DNS entry and request going to different machine.IP, PortNumber – can be specified to identify this issue.) (This is needed to get port of named instances. (Note that telnet is the best test possible to detect this). There can be multiple reasons for this error, including these, based on work I’ve done with clients and queries I’ve responded to in user forums: Verify that the instance name is correct and that SQL Server is configured to allow remote connections The server was not found or was not accessible. Scenario 1: Login request not reaching SQL ServerĪ typical error received by a client might be: A network-related or instance-specific error occurred while establishing a connection to SQL Server.

Let’s look at each of these scenarios in this article. Login request reaching SQL Server and then failing.In fact, many DBAs report connectivity issues with SQL Server as among the most frequently encountered errors. These errors can further be classified into two sub-categories:

When asked about common errors encountered in a SQL Server environment, you might expect to hear about high CPU issues, but in reality, these are rare and few.

Login failed for user sql error 18456